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Peralta J, DuPriest B, Orozco D, Pacheco JR, Martins L, Soriano RA, Wong A, Wong R, Grillo-Hill B. Drosophila Nhe2 overexpression induces autophagic cell death. Mol Biol Cell 2024; 35:br13. [PMID: 38696256 DOI: 10.1091/mbc.e24-02-0058] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/04/2024] Open
Abstract
Autophagy is a conserved catabolic process where double membrane-bound structures form around macromolecules or organelles targeted for degradation. Autophagosomes fuse with lysosomes to facilitate degradation and macromolecule recycling for homeostasis or growth in a cell autonomous manner. In cancer cells, autophagy is often up-regulated and helps cancer cells survive nutrient deprivation and stressful growth conditions. Here, we propose that the increased intracellular pH (pHi) common to cancer cells is sufficient to induce autophagic cell death. We previously developed tools to increase pHi in the Drosophila eye via overexpression of DNhe2, resulting in aberrant patterning and reduced tissue size. We examined fly eyes at earlier stages of development and found fewer interommatidial cells. We next tested whether this decrease in cell number was due to increased cell death. We found that the DNhe2-induced cell death was caspase independent, which is inconsistent with apoptosis. However, this cell death required autophagy genes, which supports autophagy as the mode of cell death. We also found that expression of molecular markers supports increased autophagy. Together, our findings suggest new roles for ion transport proteins in regulating conserved, critical developmental processes and provide evidence for new paradigms in growth control.
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Affiliation(s)
- Jobelle Peralta
- Department of Biological Sciences, San José State University, San José, CA 95112
| | - Blake DuPriest
- Department of Biological Sciences, San José State University, San José, CA 95112
| | - Daniel Orozco
- Department of Biological Sciences, San José State University, San José, CA 95112
| | - Juan Reyna Pacheco
- Department of Biological Sciences, San José State University, San José, CA 95112
| | - Laura Martins
- Department of Biological Sciences, San José State University, San José, CA 95112
| | - Rachel Ann Soriano
- Department of Biological Sciences, San José State University, San José, CA 95112
| | - Alan Wong
- Department of Biological Sciences, San José State University, San José, CA 95112
| | - Ramy Wong
- Department of Biological Sciences, San José State University, San José, CA 95112
| | - Bree Grillo-Hill
- Department of Biological Sciences, San José State University, San José, CA 95112
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2
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Catalani E, Del Quondam S, Brunetti K, Cherubini A, Bongiorni S, Taddei AR, Zecchini S, Giovarelli M, De Palma C, Perrotta C, Clementi E, Prantera G, Cervia D. Neuroprotective role of plumbagin on eye damage induced by high-sucrose diet in adult fruit fly Drosophila melanogaster. Biomed Pharmacother 2023; 166:115298. [PMID: 37597318 DOI: 10.1016/j.biopha.2023.115298] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2023] [Revised: 08/03/2023] [Accepted: 08/05/2023] [Indexed: 08/21/2023] Open
Abstract
The natural compound plumbagin has a wide range of pharmacological and potential therapeutic activities, although its role in neuroretina degeneration is unknown. Here we evaluated the effects of plumbagin on retina homeostasis of the fruit fly Drosophila melanogaster fed with high glucose diet, a model of hyperglycemia-induced eye impairment to study the pathophysiology of diabetic retinopathy at the early stages. To this aim, the visual system of flies orally administered with plumbagin has been analyzed at structural, functional, and molecular/cellular level as for instance neuronal apoptosis/autophagy dysregulation and oxidative stress-related signals. Our results demonstrated that plumbagin ameliorates the visual performance of hyperglycemic flies. Drosophila eye-structure, clearly altered by hyperglycemia, i.e. defects of the pattern of ommatidia, irregular rhabdomeres, vacuoles, damaged mitochondria, and abnormal phototransduction units were rescued, at least in part, by plumbagin. In addition, it reactivated autophagy, decreased the presence of cell death/apoptotic features, and exerted antioxidant effects in the retina. In terms of mechanisms favoring death/survival ratio, Nrf2 signaling activation may be one of the strategies by which plumbagin reduced redox unbalance mainly increasing the levels of glutathione-S-transferase. Likewise, plumbagin may act additively and/or synergistically inhibiting the mitochondrial-endoplasmic reticulum stress and unfolded protein response pathways, which prevented neuronal impairment and eye damage induced by reactive oxygen species. These results provide an avenue for further studies, which may be helpful to develop novel therapeutic candidates and drug targets against eye neurotoxicity by high glucose, a key aspect in retinal complications of diabetes.
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Affiliation(s)
- Elisabetta Catalani
- Department for Innovation in Biological, Agro-food and Forest systems (DIBAF), Università degli Studi della Tuscia, largo dell'Università snc, 01100 Viterbo, Italy
| | - Simona Del Quondam
- Department for Innovation in Biological, Agro-food and Forest systems (DIBAF), Università degli Studi della Tuscia, largo dell'Università snc, 01100 Viterbo, Italy
| | - Kashi Brunetti
- Department for Innovation in Biological, Agro-food and Forest systems (DIBAF), Università degli Studi della Tuscia, largo dell'Università snc, 01100 Viterbo, Italy
| | - Agnese Cherubini
- Department for Innovation in Biological, Agro-food and Forest systems (DIBAF), Università degli Studi della Tuscia, largo dell'Università snc, 01100 Viterbo, Italy
| | - Silvia Bongiorni
- Department of Ecological and Biological Sciences (DEB), Università degli Studi della Tuscia, largo dell'Università snc, 01100 Viterbo, Italy
| | - Anna Rita Taddei
- Section of Electron Microscopy, Great Equipment Center, Università degli Studi della Tuscia, largo dell'Università snc, 01100 Viterbo, Italy
| | - Silvia Zecchini
- Department of Biomedical and Clinical Sciences (DIBIC), Università degli Studi di Milano, via G.B. Grassi 74, 20157 Milano, Italy
| | - Matteo Giovarelli
- Department of Biomedical and Clinical Sciences (DIBIC), Università degli Studi di Milano, via G.B. Grassi 74, 20157 Milano, Italy
| | - Clara De Palma
- Department of Medical Biotechnology and Translational Medicine (BioMeTra), Università degli Studi di Milano, via L. Vanvitelli 32, 20129 Milano, Italy
| | - Cristiana Perrotta
- Department of Biomedical and Clinical Sciences (DIBIC), Università degli Studi di Milano, via G.B. Grassi 74, 20157 Milano, Italy
| | - Emilio Clementi
- Department of Biomedical and Clinical Sciences (DIBIC), Università degli Studi di Milano, via G.B. Grassi 74, 20157 Milano, Italy; Scientific Institute IRCCS "Eugenio Medea", via Don Luigi Monza 20, 23842 Bosisio Parini, Italy
| | - Giorgio Prantera
- Department of Ecological and Biological Sciences (DEB), Università degli Studi della Tuscia, largo dell'Università snc, 01100 Viterbo, Italy
| | - Davide Cervia
- Department for Innovation in Biological, Agro-food and Forest systems (DIBAF), Università degli Studi della Tuscia, largo dell'Università snc, 01100 Viterbo, Italy.
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3
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Chimata AV, Darnell H, Raj A, Kango-Singh M, Singh A. Transcriptional pausing factor M1BP regulates cellular homeostasis by suppressing autophagy and apoptosis in Drosophila eye. AUTOPHAGY REPORTS 2023; 2:2252307. [PMID: 37746026 PMCID: PMC10512699 DOI: 10.1080/27694127.2023.2252307] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/10/2023] [Revised: 07/26/2023] [Accepted: 08/23/2023] [Indexed: 09/26/2023]
Abstract
During organogenesis cellular homeostasis plays a crucial role in patterning and growth. The role of promoter proximal pausing of RNA polymerase II, which regulates transcription of several developmental genes by GAGA factor or Motif 1 Binding Protein (M1BP), has not been fully understood in cellular homeostasis. Earlier, we reported that M1BP, a functional homolog of ZKSCAN3, regulates wingless and caspase-dependent cell death (apoptosis) in the Drosophila eye. Further, blocking apoptosis does not fully rescue the M1BPRNAi phenotype of reduced eye. Therefore, we looked for other possible mechanism(s). In a forward genetic screen, members of the Jun-amino-terminal-(NH2)-Kinase (JNK) pathway were identified. Downregulation of M1BP ectopically induces JNK, a pro-death pathway known to activate both apoptosis and caspase-independent (autophagy) cell death. Activation of JNK pathway components can enhance M1BPRNAi phenotype and vice-versa. Downregulation of M1BP ectopically induced JNK signaling, which leads to apoptosis and autophagy. Apoptosis and autophagy are regulated independently by their genetic circuitry. Here, we found that blocking either apoptosis or autophagy alone rescues the reduced eye phenotype of M1BP downregulation; whereas, blocking both apoptosis and autophagy together significantly rescues the M1BP reduced eye phenotype to near wild-type in nearly 85% progeny. This data suggests that the cellular homeostasis response demonstrated by two independent cell death mechanisms, apoptosis and autophagy, can be regulated by a common transcriptional pausing mechanism orchestrated by M1BP. Since these fundamental processes are conserved in higher organisms, this novel functional link between M1BP and regulation of both apoptosis and autophagy can be extrapolated to humans.
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Affiliation(s)
| | - Hannah Darnell
- Department of Biology, University of Dayton, Dayton, OH, USA
| | - Akanksha Raj
- Department of Biology, University of Dayton, Dayton, OH, USA
| | - Madhuri Kango-Singh
- Department of Biology, University of Dayton, Dayton, OH, USA
- Premedical Program, University of Dayton, Dayton, OH, USA
- Integrative Science and Engineering (ISE), University of Dayton, Dayton, OH, USA
| | - Amit Singh
- Department of Biology, University of Dayton, Dayton, OH, USA
- Premedical Program, University of Dayton, Dayton, OH, USA
- Center for Tissue Regeneration & Engineering (TREND), University of Dayton, Dayton, OH, USA
- Integrative Science and Engineering (ISE), University of Dayton, Dayton, OH, USA
- Center for Genomic Advocacy (TCGA), Indiana State University, Terre Haute, IN, USA
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4
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Sturm Á, Saskői É, Hotzi B, Tarnóci A, Barna J, Bodnár F, Sharma H, Kovács T, Ari E, Weinhardt N, Kerepesi C, Perczel A, Ivics Z, Vellai T. Downregulation of transposable elements extends lifespan in Caenorhabditis elegans. Nat Commun 2023; 14:5278. [PMID: 37644049 PMCID: PMC10465613 DOI: 10.1038/s41467-023-40957-9] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2018] [Accepted: 08/17/2023] [Indexed: 08/31/2023] Open
Abstract
Mobility of transposable elements (TEs) frequently leads to insertional mutations in functional DNA regions. In the potentially immortal germline, TEs are effectively suppressed by the Piwi-piRNA pathway. However, in the genomes of ageing somatic cells lacking the effects of the pathway, TEs become increasingly mobile during the adult lifespan, and their activity is associated with genomic instability. Whether the progressively increasing mobilization of TEs is a cause or a consequence of ageing remains a fundamental problem in biology. Here we show that in the nematode Caenorhabditis elegans, the downregulation of active TE families extends lifespan. Ectopic activation of Piwi proteins in the soma also promotes longevity. Furthermore, DNA N6-adenine methylation at TE stretches gradually rises with age, and this epigenetic modification elevates their transcription as the animal ages. These results indicate that TEs represent a novel genetic determinant of ageing, and that N6-adenine methylation plays a pivotal role in ageing control.
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Affiliation(s)
- Ádám Sturm
- Department of Genetics, Eötvös Loránd University (ELTE), 1117, Budapest, Hungary
- Eötvös Loránd Research Network (ELKH)-ELTE Genetics Research Group, 1117, Budapest, Hungary
| | - Éva Saskői
- Department of Genetics, Eötvös Loránd University (ELTE), 1117, Budapest, Hungary
| | - Bernadette Hotzi
- Department of Genetics, Eötvös Loránd University (ELTE), 1117, Budapest, Hungary
| | - Anna Tarnóci
- Eötvös Loránd Research Network (ELKH)-ELTE Genetics Research Group, 1117, Budapest, Hungary
| | - János Barna
- Eötvös Loránd Research Network (ELKH)-ELTE Genetics Research Group, 1117, Budapest, Hungary
| | - Ferenc Bodnár
- Department of Genetics, Eötvös Loránd University (ELTE), 1117, Budapest, Hungary
| | - Himani Sharma
- Department of Genetics, Eötvös Loránd University (ELTE), 1117, Budapest, Hungary
| | - Tibor Kovács
- Department of Genetics, Eötvös Loránd University (ELTE), 1117, Budapest, Hungary
| | - Eszter Ari
- Department of Genetics, Eötvös Loránd University (ELTE), 1117, Budapest, Hungary
- HCEMM-BRC Metabolic Systems Biology Research Group, 6726, Szeged, Hungary
- Synthetic and Systems Biology Unit, Institute of Biochemistry, Biological Research Centre, Eötvös Loránd Research Network (ELKH), Temesvári krt. 62, 6726, Szeged, Hungary
| | - Nóra Weinhardt
- Department of Genetics, Eötvös Loránd University (ELTE), 1117, Budapest, Hungary
| | - Csaba Kerepesi
- Institute for Computer Science and Control (SZTAKI), 1111, Budapest, Hungary
- Brigham and Women's Hospital & Harvard Medical School, Boston, MA, 02115, USA
| | - András Perczel
- Laboratory of Structural Chemistry and Biology & Hungarian Academy of Sciences (MTA)-ELTE Protein Modelling Research Group, Institute of Chemistry, Eötvös Loránd University, 1117, Budapest, Hungary
| | - Zoltán Ivics
- Division of Medical Biotechnology, Paul Ehrlich Institute, 63225, Langen, Germany
| | - Tibor Vellai
- Department of Genetics, Eötvös Loránd University (ELTE), 1117, Budapest, Hungary.
- Eötvös Loránd Research Network (ELKH)-ELTE Genetics Research Group, 1117, Budapest, Hungary.
- Vellab Biotech Ltd., 6722, Szeged, Hungary.
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5
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Metaxakis A, Pavlidis M, Tavernarakis N. Neuronal atg1 Coordinates Autophagy Induction and Physiological Adaptations to Balance mTORC1 Signalling. Cells 2023; 12:2024. [PMID: 37626835 PMCID: PMC10453232 DOI: 10.3390/cells12162024] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2023] [Revised: 08/04/2023] [Accepted: 08/05/2023] [Indexed: 08/27/2023] Open
Abstract
The mTORC1 nutrient-sensing pathway integrates metabolic and endocrine signals into the brain to evoke physiological responses to food deprivation, such as autophagy. Nevertheless, the impact of neuronal mTORC1 activity on neuronal circuits and organismal metabolism remains obscure. Here, we show that mTORC1 inhibition acutely perturbs serotonergic neurotransmission via proteostatic alterations evoked by the autophagy inducer atg1. Neuronal ATG1 alters the intracellular localization of the serotonin transporter, which increases the extracellular serotonin and stimulates the 5HTR7 postsynaptic receptor. 5HTR7 enhances food-searching behaviour and ecdysone-induced catabolism in Drosophila. Along similar lines, the pharmacological inhibition of mTORC1 in zebrafish also stimulates food-searching behaviour via serotonergic activity. These effects occur in parallel with neuronal autophagy induction, irrespective of the autophagic activity and the protein synthesis reduction. In addition, ectopic neuronal atg1 expression enhances catabolism via insulin pathway downregulation, impedes peptidergic secretion, and activates non-cell autonomous cAMP/PKA. The above exert diverse systemic effects on organismal metabolism, development, melanisation, and longevity. We conclude that neuronal atg1 aligns neuronal autophagy induction with distinct physiological modulations, to orchestrate a coordinated physiological response against reduced mTORC1 activity.
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Affiliation(s)
- Athanasios Metaxakis
- Institute of Molecular Biology and Biotechnology, Foundation for Research and Technology Hellas, Nikolaou Plastira 100, 70013 Heraklion, Crete, Greece
| | - Michail Pavlidis
- Department of Biology, University of Crete, 71409 Heraklion, Crete, Greece;
| | - Nektarios Tavernarakis
- Institute of Molecular Biology and Biotechnology, Foundation for Research and Technology Hellas, Nikolaou Plastira 100, 70013 Heraklion, Crete, Greece
- Department of Basic Sciences, Faculty of Medicine, University of Crete, 71110 Heraklion, Crete, Greece
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6
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Szinyákovics J, Keresztes F, Kiss EA, Falcsik G, Vellai T, Kovács T. Potent New Targets for Autophagy Enhancement to Delay Neuronal Ageing. Cells 2023; 12:1753. [PMID: 37443788 PMCID: PMC10341134 DOI: 10.3390/cells12131753] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2023] [Revised: 06/28/2023] [Accepted: 06/28/2023] [Indexed: 07/15/2023] Open
Abstract
Autophagy is a lysosomal-dependent degradation process of eukaryotic cells responsible for breaking down unnecessary and damaged intracellular components. Autophagic activity gradually declines with age due to genetic control, and this change contributes to the accumulation of cellular damage at advanced ages, thereby causing cells to lose their functionality and viability. This could be particularly problematic in post-mitotic cells including neurons, the mass destruction of which leads to various neurodegenerative diseases. Here, we aim to uncover new regulatory points where autophagy could be specifically activated and test these potential drug targets in neurodegenerative disease models of Drosophila melanogaster. One possible way to activate autophagy is by enhancing autophagosome-lysosome fusion that creates the autolysosome in which the enzymatic degradation happens. The HOPS (homotypic fusion and protein sorting) and SNARE (Snap receptor) protein complexes regulate the fusion process. The HOPS complex forms a bridge between the lysosome and autophagosome with the assistance of small GTPase proteins. Thus, small GTPases are essential for autolysosome maturation, and among these proteins, Rab2 (Ras-associated binding 2), Rab7, and Arl8 (Arf-like 8) are required to degrade the autophagic cargo. For our experiments, we used Drosophila melanogaster as a model organism. Nerve-specific small GTPases were silenced and overexpressed. We examined the effects of these genetic interventions on lifespan, climbing ability, and autophagy. Finally, we also studied the activation of small GTPases in a Parkinson's disease model. Our results revealed that GTP-locked, constitutively active Rab2 (Rab2-CA) and Arl8 (Arl8-CA) expression reduces the levels of the autophagic substrate p62/Ref(2)P in neurons, extends lifespan, and improves the climbing ability of animals during ageing. However, Rab7-CA expression dramatically shortens lifespan and inhibits autophagy. Rab2-CA expression also increases lifespan in a Parkinson's disease model fly strain overexpressing human mutant (A53T) α-synuclein protein. Data provided by this study suggests that Rab2 and Arl8 serve as potential targets for autophagy enhancement in the Drosophila nervous system. In the future, it might be interesting to assess the effect of Rab2 and Arl8 coactivation on autophagy, and it would also be worthwhile to validate these findings in a mammalian model and human cell lines. Molecules that specifically inhibit Rab2 or Arl8 serve as potent drug candidates to modulate the activity of the autophagic process in treating neurodegenerative pathologies. In the future, it would be reasonable to investigate which GAP enzyme can inhibit Rab2 or Arl8 specifically, but not affect Rab7, with similar medical purposes.
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Affiliation(s)
- Janka Szinyákovics
- Department of Genetics, Eötvös Loránd University (ELTE), H-1117 Budapest, Hungary
- Doctoral School of Biology, Institute of Biology, ELTE Eötvös Loránd University (ELTE), Pázmány Péter sétány 1/C, H-1117 Budapest, Hungary
- ELKH-ELTE Genetic Research Group, H-1117 Budapest, Hungary
| | - Fanni Keresztes
- Department of Genetics, Eötvös Loránd University (ELTE), H-1117 Budapest, Hungary
- Doctoral School of Biology, Institute of Biology, ELTE Eötvös Loránd University (ELTE), Pázmány Péter sétány 1/C, H-1117 Budapest, Hungary
| | - Eszter Anna Kiss
- Department of Genetics, Eötvös Loránd University (ELTE), H-1117 Budapest, Hungary
| | - Gergő Falcsik
- Department of Genetics, Eötvös Loránd University (ELTE), H-1117 Budapest, Hungary
| | - Tibor Vellai
- Department of Genetics, Eötvös Loránd University (ELTE), H-1117 Budapest, Hungary
- ELKH-ELTE Genetic Research Group, H-1117 Budapest, Hungary
| | - Tibor Kovács
- Department of Genetics, Eötvös Loránd University (ELTE), H-1117 Budapest, Hungary
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7
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Komlós M, Szinyákovics J, Falcsik G, Sigmond T, Jezsó B, Vellai T, Kovács T. The Small-Molecule Enhancers of Autophagy AUTEN-67 and -99 Delay Ageing in Drosophila Striated Muscle Cells. Int J Mol Sci 2023; 24:ijms24098100. [PMID: 37175806 PMCID: PMC10179358 DOI: 10.3390/ijms24098100] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2023] [Revised: 04/26/2023] [Accepted: 04/28/2023] [Indexed: 05/15/2023] Open
Abstract
Autophagy (cellular self-degradation) plays a major role in maintaining the functional integrity (homeostasis) of essentially all eukaryotic cells. During the process, superfluous and damaged cellular constituents are delivered into the lysosomal compartment for enzymatic degradation. In humans, age-related defects in autophagy have been linked to the incidence of various age-associated degenerative pathologies (e.g., cancer, neurodegenerative diseases, diabetes, tissue atrophy and fibrosis, and immune deficiency) and accelerated ageing. Muscle mass decreases at detectable levels already in middle-aged patients, and this change can increase up to 30-50% at age 80. AUTEN-67 and -99, two small-molecule enhancers of autophagy with cytoprotective and anti-ageing effects have been previously identified and initially characterized. These compounds can increase the life span in wild-type and neurodegenerative model strains of the fruit fly Drosophila melanogaster. Adult flies were treated with these AUTEN molecules via feeding. Fluorescence and electron microscopy and Western blotting were used to assess the level of autophagy and cellular senescence. Flying tests were used to measure the locomotor ability of the treated animals at different ages. In the current study, the effects of AUTEN-67 and -99 were observed on striated muscle cells using the Drosophila indirect flight muscle (IFM) as a model. The two molecules were capable of inducing autophagy in IFM cells, thereby lowering the accumulation of protein aggregates and damaged mitochondria, both characterizing muscle ageing. Furthermore, the two molecules significantly improved the flying ability of treated animals. AUTEN-67 and -99 decrease the rate at which striated muscle cells age. These results may have a significant medical relevance that could be further examined in mammalian models.
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Affiliation(s)
- Marcell Komlós
- Department of Genetics, ELTE Eötvös Loránd University, 1117 Budapest, Hungary
| | - Janka Szinyákovics
- Department of Genetics, ELTE Eötvös Loránd University, 1117 Budapest, Hungary
- MTA-ELTE Genetic Research Group, 1117 Budapest, Hungary
| | - Gergő Falcsik
- Department of Genetics, ELTE Eötvös Loránd University, 1117 Budapest, Hungary
| | - Tímea Sigmond
- Department of Genetics, ELTE Eötvös Loránd University, 1117 Budapest, Hungary
| | - Bálint Jezsó
- Department of Anatomy, Cell and Developmental Biology, ELTE Eötvös Loránd University, 1117 Budapest, Hungary
- Institute of Enzymology, Research Center for Natural Sciences, Eötvös Loránd Research Network, 1117 Budapest, Hungary
| | - Tibor Vellai
- Department of Genetics, ELTE Eötvös Loránd University, 1117 Budapest, Hungary
- MTA-ELTE Genetic Research Group, 1117 Budapest, Hungary
| | - Tibor Kovács
- Department of Genetics, ELTE Eötvös Loránd University, 1117 Budapest, Hungary
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8
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Dutta SB, Linneweber GA, Andriatsilavo M, Hiesinger PR, Hassan BA. EGFR-dependent suppression of synaptic autophagy is required for neuronal circuit development. Curr Biol 2023; 33:517-532.e5. [PMID: 36640763 DOI: 10.1016/j.cub.2022.12.039] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2022] [Revised: 10/31/2022] [Accepted: 12/14/2022] [Indexed: 01/15/2023]
Abstract
The development of neuronal connectivity requires stabilization of dynamic axonal branches at sites of synapse formation. Models that explain how axonal branching is coupled to synaptogenesis postulate molecular regulators acting in a spatiotemporally restricted fashion to ensure branching toward future synaptic partners while also stabilizing the emerging synaptic contacts between such partners. We investigated this question using neuronal circuit development in the Drosophila brain as a model system. We report that epidermal growth factor receptor (EGFR) activity is required in presynaptic axonal branches during two distinct temporal intervals to regulate circuit wiring in the developing Drosophila visual system. EGFR is required early to regulate primary axonal branching. EGFR activity is then independently required at a later stage to prevent degradation of the synaptic active zone protein Bruchpilot (Brp). Inactivation of EGFR results in a local increase of autophagy in presynaptic branches and the translocation of active zone proteins into autophagic vesicles. The protection of synaptic material during this later interval of wiring ensures the stabilization of terminal branches, circuit connectivity, and appropriate visual behavior. Phenotypes of EGFR inactivation can be rescued by increasing Brp levels or downregulating autophagy. In summary, we identify a temporally restricted molecular mechanism required for coupling axonal branching and synaptic stabilization that contributes to the emergence of neuronal wiring specificity.
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Affiliation(s)
- Suchetana B Dutta
- Institut du Cerveau-Paris Brain Institute (ICM), Sorbonne Université, Inserm, CNRS, Hôpital Pitié Salpêtrière, 75013 Paris, France; Division of Neurobiology, Free University of Berlin, 14195 Berlin, Germany; Einstein-BIH, Charité Universitätsmedizin, 10117 Berlin, Germany
| | | | - Maheva Andriatsilavo
- Institut du Cerveau-Paris Brain Institute (ICM), Sorbonne Université, Inserm, CNRS, Hôpital Pitié Salpêtrière, 75013 Paris, France; Division of Neurobiology, Free University of Berlin, 14195 Berlin, Germany; Einstein-BIH, Charité Universitätsmedizin, 10117 Berlin, Germany
| | | | - Bassem A Hassan
- Institut du Cerveau-Paris Brain Institute (ICM), Sorbonne Université, Inserm, CNRS, Hôpital Pitié Salpêtrière, 75013 Paris, France; Division of Neurobiology, Free University of Berlin, 14195 Berlin, Germany; Einstein-BIH, Charité Universitätsmedizin, 10117 Berlin, Germany.
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9
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A conserved MTMR lipid phosphatase increasingly suppresses autophagy in brain neurons during aging. Sci Rep 2022; 12:21817. [PMID: 36528685 PMCID: PMC9759524 DOI: 10.1038/s41598-022-24843-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2021] [Accepted: 11/21/2022] [Indexed: 12/23/2022] Open
Abstract
Ageing is driven by the progressive, lifelong accumulation of cellular damage. Autophagy (cellular self-eating) functions as a major cell clearance mechanism to degrade such damages, and its capacity declines with age. Despite its physiological and medical significance, it remains largely unknown why autophagy becomes incapable of effectively eliminating harmful cellular materials in many cells at advanced ages. Here we show that age-associated defects in autophagic degradation occur at both the early and late stages of the process. Furthermore, in the fruit fly Drosophila melanogaster, the myotubularin-related (MTMR) lipid phosphatase egg-derived tyrosine phosphatase (EDTP) known as an autophagy repressor gradually accumulates in brain neurons during the adult lifespan. The age-related increase in EDTP activity is associated with a growing DNA N6-adenine methylation at EDTP locus. MTMR14, the human counterpart of EDTP, also tends to accumulate with age in brain neurons. Thus, EDTP, and presumably MTMR14, promotes brain ageing by increasingly suppressing autophagy throughout adulthood. We propose that EDTP and MTMR14 phosphatases operate as endogenous pro-ageing factors setting the rate at which neurons age largely independently of environmental factors, and that autophagy is influenced by DNA N6-methyladenine levels in insects.
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10
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Varga VB, Keresztes F, Sigmond T, Vellai T, Kovács T. The evolutionary and functional divergence of the Atg8 autophagy protein superfamily. Biol Futur 2022; 73:375-384. [PMID: 35731422 DOI: 10.1007/s42977-022-00123-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2022] [Accepted: 05/28/2022] [Indexed: 01/27/2023]
Abstract
Autophagy is a highly conserved self-degradation process of eukaryotic cells which is required for the effective elimination of damaged and unnecessary cytosolic constituents. Defects in the process can cause the intracellular accumulation of such damages, thereby leading to the senescence and subsequent loss of the affected cell. Defective autophagy hence is implicated in the development of various degenerative processes, including cancer, neurodegenerative diseases, diabetes, tissue atrophy and fibrosis, and immune deficiency, as well as in accelerated aging. The autophagic process is mediated by numerous autophagy-related (ATG) proteins, among which the ATG8/LC3/GABARAP (Microtubule-associated protein 1A/1B-light chain 3/Gammaaminobutyric acid receptor-associated protein) superfamily has a pivotal role in the formation and maturation of autophagosome, a key (macro) autophagic structure (the autophagosome sequesters parts of the cytoplasm which are destined for breakdown). While in the unicellular yeast there is only a single ATG8 protein, metazoan systems usually contain more ATG8 paralogs. ATG8 paralogs generally display tissue-specific expression patterns and their functions are not strictly restricted to autophagy. For example, GABARAP proteins also play a role in intracellular vesicle transport, and, in addition to autophagosome formation, ATG8 also functions in selective autophagy. In this review, we summarize the functional diversity of ATG8/LC3/GABARAP proteins, using tractable genetic models applied in autophagy research.
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Affiliation(s)
- Virginia B Varga
- Department of Genetics, Institute of Biology, ELTE Eötvös Loránd University, Pázmány Péter sétány 1/C, Budapest, H-1117, Hungary
| | - Fanni Keresztes
- Department of Genetics, Institute of Biology, ELTE Eötvös Loránd University, Pázmány Péter sétány 1/C, Budapest, H-1117, Hungary
| | - Tímea Sigmond
- Department of Genetics, Institute of Biology, ELTE Eötvös Loránd University, Pázmány Péter sétány 1/C, Budapest, H-1117, Hungary
| | - Tibor Vellai
- Department of Genetics, Institute of Biology, ELTE Eötvös Loránd University, Pázmány Péter sétány 1/C, Budapest, H-1117, Hungary.,ELKH-ELTE Genetics Research Group, Pázmány Péter sétány 1/C, Budapest, H-1117, Hungary
| | - Tibor Kovács
- Department of Genetics, Institute of Biology, ELTE Eötvös Loránd University, Pázmány Péter sétány 1/C, Budapest, H-1117, Hungary.
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11
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Autophagy is required for spermatogonial differentiation in the Drosophila testis. Biol Futur 2022; 73:187-204. [DOI: 10.1007/s42977-022-00122-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2021] [Accepted: 05/13/2022] [Indexed: 10/18/2022]
Abstract
AbstractAutophagy is a conserved, lysosome-dependent catabolic process of eukaryotic cells which is involved in cellular differentiation. Here, we studied its specific role in the differentiation of spermatogonial cells in the Drosophila testis. In the apical part of the Drosophila testis, there is a niche of germline stem cells (GSCs), which are connected to hub cells. Hub cells emit a ligand for bone morhphogenetic protein (BMP)-mediated signalling that represses Bam (bag of marbles) expression in GSCs to maintain them in an undifferentiated state. GSCs divide asymmetrically, and one of the daughter cells differentiates into a gonialblast, which eventually generates a cluster of spermatogonia (SG) by mitoses. Bam is active in SG, and defects in Bam function arrest these cells at mitosis. We show that BMP signalling represses autophagy in GSCs, but upregulates the process in SG. Inhibiting autophagy in SG results in an overproliferating phenotype similar to that caused by bam mutations. Furthermore, Bam deficiency leads to a failure in downstream mechanisms of the autophagic breakdown. These results suggest that the BMP-Bam signalling axis regulates developmental autophagy in the Drosophila testis, and that acidic breakdown of cellular materials is required for spermatogonial differentiation.
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12
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Hernandez-Diaz S, Ghimire S, Sanchez-Mirasierra I, Montecinos-Oliva C, Swerts J, Kuenen S, Verstreken P, Soukup SF. Endophilin-B regulates autophagy during synapse development and neurodegeneration. Neurobiol Dis 2021; 163:105595. [PMID: 34933093 DOI: 10.1016/j.nbd.2021.105595] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2021] [Revised: 12/13/2021] [Accepted: 12/17/2021] [Indexed: 01/18/2023] Open
Abstract
Synapses are critical for neuronal communication and brain function. To maintain neuronal homeostasis, synapses rely on autophagy. Autophagic alterations cause neurodegeneration and synaptic dysfunction is a feature in neurodegenerative diseases. In Parkinson's disease (PD), where the loss of synapses precedes dopaminergic neuron loss, various PD-causative proteins are involved in the regulation of autophagy. So far only a few factors regulating autophagy at the synapse have been identified and the molecular mechanisms underlying autophagy at the synapse is only partially understood. Here, we describe Endophilin-B (EndoB) as a novel player in the regulation of synaptic autophagy in health and disease. We demonstrate that EndoB is required for autophagosome biogenesis at the synapse, whereas the loss of EndoB blocks the autophagy induction promoted by the PD mutation LRRK2G2019S. We show that EndoB is required to prevent neuronal loss. Moreover, loss of EndoB in the Drosophila visual system leads to an increase in synaptic contacts between photoreceptor terminals and their post-synaptic synapses. These data confirm the role of autophagy in synaptic contact formation and neuronal survival.
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Affiliation(s)
| | - Saurav Ghimire
- Univ. Bordeaux, CNRS, IMN, UMR 5293, F-33000 Bordeaux, France
| | | | | | - Jef Swerts
- VIB Center for the Biology of Disease, Belgium; KU Leuven, Department for Human Genetics, Leuven Institute for Neurodegenerative Disease (LIND), 3000 Leuven, Belgium
| | - Sabine Kuenen
- VIB Center for the Biology of Disease, Belgium; KU Leuven, Department for Human Genetics, Leuven Institute for Neurodegenerative Disease (LIND), 3000 Leuven, Belgium
| | - Patrik Verstreken
- VIB Center for the Biology of Disease, Belgium; KU Leuven, Department for Human Genetics, Leuven Institute for Neurodegenerative Disease (LIND), 3000 Leuven, Belgium
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13
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Nutraceutical Strategy to Counteract Eye Neurodegeneration and Oxidative Stress in Drosophila melanogaster Fed with High-Sugar Diet. Antioxidants (Basel) 2021; 10:antiox10081197. [PMID: 34439445 PMCID: PMC8388935 DOI: 10.3390/antiox10081197] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2021] [Revised: 07/22/2021] [Accepted: 07/25/2021] [Indexed: 12/14/2022] Open
Abstract
Aberrant production of reactive oxygen species (ROS) is a common feature of damaged retinal neurons in diabetic retinopathy, and antioxidants may exert both preventive and therapeutic action. To evaluate the beneficial and antioxidant properties of food supplementation with Lisosan G, a powder of bran and germ of grain (Triticum aestivum) obtained by fermentation with selected lactobacillus and natural yeast strains, we used an in vivo model of hyperglycemia-induced retinal damage, the fruit fly Drosophila melanogaster fed with high-sucrose diet. Lisosan G positively affected the visual system of hyperglycemic flies at structural/functional level, decreased apoptosis, and reactivated protective autophagy at the retina internal network. Also, in high sucrose-fed Drosophila, Lisosan G reduced the levels of brain ROS and retina peroxynitrite. The analysis of oxidative stress-related metabolites suggested 7,8-dihydrofolate, uric acid, dihydroorotate, γ-L-glutamyl-L-cysteine, allantoin, cysteinyl-glycine, and quinolate as key mediators of Lisosan G-induced inhibition of neuronal ROS, along with the upregulation of glutathione system. Of note, Lisosan G may impact oxidative stress and the ensuing retinal cell death, also independently from autophagy, although the autophagy-ROS cross-talk is critical. This study demonstrated that the continuous supplementation with the alimentary integrator Lisosan G exerts a robust and multifaceted antioxidant effect on retinal neurons, thus providing efficacious neuroprotection of hyperglycemic eye.
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14
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DNase II mediates a parthanatos-like developmental cell death pathway in Drosophila primordial germ cells. Nat Commun 2021; 12:2285. [PMID: 33863891 PMCID: PMC8052343 DOI: 10.1038/s41467-021-22622-1] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2020] [Accepted: 03/23/2021] [Indexed: 02/02/2023] Open
Abstract
During Drosophila embryonic development, cell death eliminates 30% of the primordial germ cells (PGCs). Inhibiting apoptosis does not prevent PGC death, suggesting a divergence from the conventional apoptotic program. Here, we demonstrate that PGCs normally activate an intrinsic alternative cell death (ACD) pathway mediated by DNase II release from lysosomes, leading to nuclear translocation and subsequent DNA double-strand breaks (DSBs). DSBs activate the DNA damage-sensing enzyme, Poly(ADP-ribose) (PAR) polymerase-1 (PARP-1) and the ATR/Chk1 branch of the DNA damage response. PARP-1 and DNase II engage in a positive feedback amplification loop mediated by the release of PAR polymers from the nucleus and the nuclear accumulation of DNase II in an AIF- and CypA-dependent manner, ultimately resulting in PGC death. Given the anatomical and molecular similarities with an ACD pathway called parthanatos, these findings reveal a parthanatos-like cell death pathway active during Drosophila development.
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15
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Manzéger A, Tagscherer K, Lőrincz P, Szaker H, Lukácsovich T, Pilz P, Kméczik R, Csikós G, Erdélyi M, Sass M, Kovács T, Vellai T, Billes VA. Condition-dependent functional shift of two Drosophila Mtmr lipid phosphatases in autophagy control. Autophagy 2021; 17:4010-4028. [PMID: 33779490 PMCID: PMC8726729 DOI: 10.1080/15548627.2021.1899681] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Myotubularin (MTM) and myotubularin-related (MTMR) lipid phosphatases catalyze the removal of a phosphate group from certain phosphatidylinositol derivatives. Because some of these substrates are required for macroautophagy/autophagy, during which unwanted cytoplasmic constituents are delivered into lysosomes for degradation, MTM and MTMRs function as important regulators of the autophagic process. Despite its physiological and medical significance, the specific role of individual MTMR paralogs in autophagy control remains largely unexplored. Here we examined two Drosophila MTMRs, EDTP and Mtmr6, the fly orthologs of mammalian MTMR14 and MTMR6 to MTMR8, respectively, and found that these enzymes affect the autophagic process in a complex, condition-dependent way. EDTP inhibited basal autophagy, but did not influence stress-induced autophagy. In contrast, Mtmr6 promoted the process under nutrient-rich settings, but effectively blocked its hyperactivation in response to stress. Thus, Mtmr6 is the first identified MTMR phosphatase with dual, antagonistic roles in the regulation of autophagy, and shows conditional antagonism/synergism with EDTP in modulating autophagic breakdown. These results provide a deeper insight into the adjustment of autophagy. Abbreviations: Atg, autophagy-related; BDSC, Bloomington Drosophila Stock Center; DGRC, Drosophila Genetic Resource Center; EDTP, Egg-derived tyrosine phosphatase; FYVE, zinc finger domain from Fab1 (yeast ortholog of PIKfyve), YOTB, Vac1 (vesicle transport protein) and EEA1 cysteine-rich proteins; LTR, LysoTracker Red; MTM, myotubularin; MTMR, myotubularin-related; PI, phosphatidylinositol; Pi3K59F, Phosphotidylinositol 3 kinase 59F; PtdIns3P, phosphatidylinositol-3-phosphate; PtdIns(3,5)P2, phosphatidylinositol-3,5-bisphosphate; PtdIns5P, phosphatidylinositol-5-phosphate; ref(2)P, refractory to sigma P; Syx17, Syntaxin 17; TEM, transmission electron microscopy; UAS, upstream activating sequence; Uvrag, UV-resistance associated gene; VDRC, Vienna Drosophila RNAi Center; Vps34, Vacuolar protein sorting 34.
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Affiliation(s)
- Anna Manzéger
- Department of Genetics, ELTE Eötvös Loránd University, Budapest, Hungary.,MTA-ELTE Genetics Research Group, Budapest, Hungary
| | - Kinga Tagscherer
- Department of Genetics, ELTE Eötvös Loránd University, Budapest, Hungary
| | - Péter Lőrincz
- Department of Anatomy, Cell and Developmental Biology, ELTE Eötvös Loránd University, Budapest, Hungary.,Hungarian Academy of Sciences, Premium Postdoctoral Research Program, Budapest, Hungary
| | - Henrik Szaker
- Department of Genetics, ELTE Eötvös Loránd University, Budapest, Hungary
| | - Tamás Lukácsovich
- Department of Developmental and Cell Biology, University of California, Irvine, CA, USA
| | - Petra Pilz
- Department of Genetics, ELTE Eötvös Loránd University, Budapest, Hungary
| | - Regina Kméczik
- Department of Genetics, ELTE Eötvös Loránd University, Budapest, Hungary
| | - George Csikós
- Department of Anatomy, Cell and Developmental Biology, ELTE Eötvös Loránd University, Budapest, Hungary
| | - Miklós Erdélyi
- Institute of Genetics, Biological Research Centre, Szeged, Hungary
| | - Miklós Sass
- Department of Anatomy, Cell and Developmental Biology, ELTE Eötvös Loránd University, Budapest, Hungary
| | - Tibor Kovács
- Department of Genetics, ELTE Eötvös Loránd University, Budapest, Hungary
| | - Tibor Vellai
- Department of Genetics, ELTE Eötvös Loránd University, Budapest, Hungary.,MTA-ELTE Genetics Research Group, Budapest, Hungary
| | - Viktor A Billes
- Department of Genetics, ELTE Eötvös Loránd University, Budapest, Hungary.,MTA-ELTE Genetics Research Group, Budapest, Hungary
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16
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Catalani E, Silvestri F, Bongiorni S, Taddei AR, Fanelli G, Rinalducci S, De Palma C, Perrotta C, Prantera G, Cervia D. Retinal damage in a new model of hyperglycemia induced by high-sucrose diets. Pharmacol Res 2021; 166:105488. [PMID: 33582248 DOI: 10.1016/j.phrs.2021.105488] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/01/2021] [Revised: 02/08/2021] [Accepted: 02/08/2021] [Indexed: 12/13/2022]
Abstract
Loss of retinal neurons may precede clinical signs of diabetic retinopathy (DR). We studied for the first time the effects of hyperglycemia on the visual system of the fruit fly Drosophila melanogaster to characterize a model for glucose-induced retinal neurodegeneration, thus complementing more traditional vertebrate systems. Adult flies were fed with increased high-sucrose regimens which did not modify the locomotion ability, muscle phenotype and mobility after 10 days. The increased availability of dietary sucrose induced hyperglycemia and phosphorylation of Akt in fat tissue, without significant effects on adult growth and viability, consistent with the early phase of insulin signaling and a low impact on the overall metabolic profile of flies at short term. Noteworthy, high-sucrose diets significantly decreased Drosophila responsiveness to the light as a consequence of vision defects. Hyperglycemia did not alter the gross anatomical architecture of the external eye phenotype although a progressive damage of photosensitive units was observed. Appreciable levels of cleaved caspase 3 and nitrotyrosine were detected in the internal retina network as well as punctate staining of Light-Chain 3 and p62, and accumulated autophagosomes, indicating apoptotic features, peroxynitrite formation and autophagy turnover defects. In summary, our results in Drosophila support the view that hyperglycemia induced by high-sucrose diets lead to eye defects, apoptosis/autophagy dysregulation, oxidative stress, and visual dysfunctions which are evolutionarily conserved, thus offering a meaningful opportunity of using a simple in vivo model to study the pathophysiology of neuroretinal alterations that develop in patients at the early stages of DR.
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Affiliation(s)
- Elisabetta Catalani
- Department for Innovation in Biological, Agro-food and Forest Systems (DIBAF), Università degli Studi della Tuscia, largo dell'Università snc, 01100 Viterbo, Italy
| | - Federica Silvestri
- Department for Innovation in Biological, Agro-food and Forest Systems (DIBAF), Università degli Studi della Tuscia, largo dell'Università snc, 01100 Viterbo, Italy
| | - Silvia Bongiorni
- Department of Ecological and Biological Sciences (DEB), Università degli Studi della Tuscia, largo dell'Università snc, 01100 Viterbo, Italy
| | - Anna Rita Taddei
- Section of Electron Microscopy, Great Equipment Center, Università degli Studi della Tuscia, largo dell'Università snc, 01100 Viterbo, Italy
| | - Giuseppina Fanelli
- Department of Ecological and Biological Sciences (DEB), Università degli Studi della Tuscia, largo dell'Università snc, 01100 Viterbo, Italy
| | - Sara Rinalducci
- Department of Ecological and Biological Sciences (DEB), Università degli Studi della Tuscia, largo dell'Università snc, 01100 Viterbo, Italy
| | - Clara De Palma
- Department of Medical Biotechnology and Translational Medicine (BioMeTra), Università degli Studi di Milano, via L. Vanvitelli 32, 20129 Milano, Italy
| | - Cristiana Perrotta
- Department of Biomedical and Clinical Sciences "Luigi Sacco" (DIBIC), Università degli Studi di Milano, via G.B. Grassi 74, 20157 Milano, Italy
| | - Giorgio Prantera
- Department of Ecological and Biological Sciences (DEB), Università degli Studi della Tuscia, largo dell'Università snc, 01100 Viterbo, Italy
| | - Davide Cervia
- Department for Innovation in Biological, Agro-food and Forest Systems (DIBAF), Università degli Studi della Tuscia, largo dell'Università snc, 01100 Viterbo, Italy.
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17
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Catalani E, Bongiorni S, Taddei AR, Mezzetti M, Silvestri F, Coazzoli M, Zecchini S, Giovarelli M, Perrotta C, De Palma C, Clementi E, Ceci M, Prantera G, Cervia D. Defects of full-length dystrophin trigger retinal neuron damage and synapse alterations by disrupting functional autophagy. Cell Mol Life Sci 2020; 78:1615-1636. [PMID: 32749504 PMCID: PMC7904721 DOI: 10.1007/s00018-020-03598-5] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2020] [Revised: 06/10/2020] [Accepted: 07/09/2020] [Indexed: 02/06/2023]
Abstract
Dystrophin (dys) mutations predispose Duchenne muscular disease (DMD) patients to brain and retinal complications. Although different dys variants, including long dys products, are expressed in the retina, their function is largely unknown. We investigated the putative role of full-length dystrophin in the homeostasis of neuro-retina and its impact on synapsis stabilization and cell fate. Retinas of mdx mice, the most used DMD model which does not express the 427-KDa dys protein (Dp427), showed overlapped cell death and impaired autophagy. Apoptotic neurons in the outer plexiform/inner nuclear layer and the ganglion cell layer had an impaired autophagy with accumulated autophagosomes. The autophagy dysfunction localized at photoreceptor axonal terminals and bipolar, amacrine, and ganglion cells. The absence of Dp427 does not cause a severe phenotype but alters the neuronal architecture, compromising mainly the pre-synaptic photoreceptor terminals and their post-synaptic sites. The analysis of two dystrophic mutants of the fruit fly Drosophila melanogaster, the homozygous DysE17 and DysEP3397, lacking functional large-isoforms of dystrophin-like protein, revealed rhabdomere degeneration. Structural damages were evident in the internal network of retina/lamina where photoreceptors make the first synapse. Both accumulated autophagosomes and apoptotic features were detected and the visual system was functionally impaired. The reactivation of the autophagosome turnover by rapamycin prevented neuronal cell death and structural changes of mutant flies and, of interest, sustained autophagy ameliorated their response to light. Overall, these findings indicate that functional full-length dystrophin is required for synapsis stabilization and neuronal survival of the retina, allowing also proper autophagy as a prerequisite for physiological cell fate and visual properties.
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Affiliation(s)
- Elisabetta Catalani
- Department for Innovation in Biological, Agro-Food and Forest Systems (DIBAF), Università degli Studi della Tuscia, largo dell'Università snc, 01100, Viterbo, Italy
| | - Silvia Bongiorni
- Department of Ecological and Biological Sciences (DEB), Università degli Studi della Tuscia, largo dell'Università snc, 01100, Viterbo, Italy
| | - Anna Rita Taddei
- Section of Electron Microscopy, Great Equipment Center, Università degli Studi della Tuscia, largo dell'Università snc, 01100, Viterbo, Italy
| | - Marta Mezzetti
- Department for Innovation in Biological, Agro-Food and Forest Systems (DIBAF), Università degli Studi della Tuscia, largo dell'Università snc, 01100, Viterbo, Italy
| | - Federica Silvestri
- Department for Innovation in Biological, Agro-Food and Forest Systems (DIBAF), Università degli Studi della Tuscia, largo dell'Università snc, 01100, Viterbo, Italy
| | - Marco Coazzoli
- Department of Biomedical and Clinical Sciences "Luigi Sacco" (DIBIC), Università degli Studi di Milano, via G.B. Grassi 74, 20157, Milano, Italy
| | - Silvia Zecchini
- Department of Biomedical and Clinical Sciences "Luigi Sacco" (DIBIC), Università degli Studi di Milano, via G.B. Grassi 74, 20157, Milano, Italy
| | - Matteo Giovarelli
- Department of Biomedical and Clinical Sciences "Luigi Sacco" (DIBIC), Università degli Studi di Milano, via G.B. Grassi 74, 20157, Milano, Italy
| | - Cristiana Perrotta
- Department of Biomedical and Clinical Sciences "Luigi Sacco" (DIBIC), Università degli Studi di Milano, via G.B. Grassi 74, 20157, Milano, Italy
| | - Clara De Palma
- Department of Medical Biotechnology and Translational Medicine (BioMeTra), Università degli Studi di Milano, via Luigi Vanvitelli 32, 20129 , Milano, Italy
| | - Emilio Clementi
- Department of Biomedical and Clinical Sciences "Luigi Sacco" (DIBIC), Università degli Studi di Milano, via G.B. Grassi 74, 20157, Milano, Italy
- Unit of Clinical Pharmacology, University Hospital "Luigi Sacco"-ASST Fatebenefratelli Sacco, via G.B. Grassi 74, 20157, Milano, Italy
- Scientific Institute IRCCS "Eugenio Medea", via Don Luigi Monza 20, 23842, Bosisio Parini (LC), Italy
| | - Marcello Ceci
- Department of Ecological and Biological Sciences (DEB), Università degli Studi della Tuscia, largo dell'Università snc, 01100, Viterbo, Italy
| | - Giorgio Prantera
- Department of Ecological and Biological Sciences (DEB), Università degli Studi della Tuscia, largo dell'Università snc, 01100, Viterbo, Italy
| | - Davide Cervia
- Department for Innovation in Biological, Agro-Food and Forest Systems (DIBAF), Università degli Studi della Tuscia, largo dell'Università snc, 01100, Viterbo, Italy.
- Department of Biomedical and Clinical Sciences "Luigi Sacco" (DIBIC), Università degli Studi di Milano, via G.B. Grassi 74, 20157, Milano, Italy.
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18
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Drosophila melanogaster as a model for arbovirus infection of adult salivary glands. Virology 2020; 543:1-6. [DOI: 10.1016/j.virol.2020.01.010] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2019] [Revised: 01/21/2020] [Accepted: 01/22/2020] [Indexed: 12/19/2022]
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19
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Molecular mechanisms of selective autophagy in Drosophila. INTERNATIONAL REVIEW OF CELL AND MOLECULAR BIOLOGY 2020; 354:63-105. [DOI: 10.1016/bs.ircmb.2019.08.003] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
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